Millions of women across the world take hormonal contraception either as birth control or to help with problem periods - but do we know how much they might be affecting our brains? In this episode India asks Dr Jackie Maybin from the University of Edinburgh, whether there is a physiological need for women to have their periods whilst on the contraceptive pill. Dr Katy Vincent explains how women today have far more periods than our recent ancestors ever did and Dr Sarah Hill, author of How the Pill Changes Everything: Your Brain on Birth Control, joins to discuss the effect of the pill on women’s brains. Credits: Presented by India Rakusen. Producer: Ellie Sans. Assistant Producer: Jorja McAndrew. Executive Producer: Suzy Grant. Original music composed and performed by Rebekah Reid. Sound Design by Charlie Brandon-King. Special thanks to all contributors and audio diarists. A Listen production for BBC Radio 4 and BBC Sounds.